By atomizing a siloxane and an organic titanium compound for flame
combustion, spherical complex oxide fine particles of amorphous
silica-titania are obtained having a particle size of 10-300 nm, a
specific surface area of 10-100 m.sup.2 /g, and a titania content of 1-99%
by weight. By hydrophobizing the fine particles and adding them to a
toner, a developer is obtained which is improved in fluidity, cleanability
and uniform and stable charging.
